Awe, wonder and gene committees

What is our place in the universe? The standard story would in any other circumstances be tragic, if not simply farcical. Received wisdom proceeds as follows: man was universally perceived as the pinnacle of creation, or at least for those favoured individuals who glanced towards the incendiary activities of the Inquisition across the backs of the toiling medieval peasantry. Now, so the story continues, the mighty frame lies toppled, as the scientific world picture reduces us to utter insignificance. Such a parody not only does violence to medieval science, but wantonly blurs the extraordinary facts of human cognition and rationality. Even so, the popular view remains that man is a worm; a cosmic accident caught unwittingly in a vice of contingent hopelessness. These three books, although very different in content, style and competence, each seek to find for this odd little biped a resting place, if not a home.

By far the most important is Michael Denton's Nature's Destiny , which attempts to restore to biology and evolution a teleological programme.

That we, and indeed all life, might be the result of purposeful activity, is in today's intellectual climate a bold, and to some an unforgivable, enterprise. When, however, Denton writes, "It is simply the most daring idea ever proposed", it is not in the hubristical vein of the Great Communicators of Science, who in any event may be left to flounder in their purple prose and self-congratulation. Rather, Denton's objective is to reinforce the notion that the growing realisation of a sense of purpose is not a quaint delusion picked up in the dawning cognition of a Miocene ape, but a true imprint of the cosmos. Given the derision with which such statements are usually greeted, it is important to realise that Denton deserves a sympathetic and intelligent hearing. I wonder if he will get it.

Of course, in some ways quite a lot of groundwork has already been achieved thanks to those cosmologists who are willing to take seriously the anthropic principle. While this has important implications for delineating the conditions under which life might emerge, not least because of a fluke-like thermonuclear reaction in the interior of stars that allows carbon to form, the principle need say nothing material about the actual emergence of life, its course of evolution or even its commonality.

Despite Denton's grand programme there are, in fact, several strands woven into the argument. Perhaps the most important, and the area I found the most persuasive, are those factors that underpin life. Most striking, surely, is the utterly peculiar nature of water. By all physico-chemical logic the ice in my gin and tonic should be lurking at the bottom of the glass: crystallised solids of liquids always sink. While such behaviour might be a local convenience for my drinking habits, in the world at large it would be an unmitigated disaster. As Denton notes, in such a contrarian universe "most of the water ... would be permanently frozen into vast beds of ice at the bottom of the oceans". To this long-appreciated quirk of density changes associated with its crystallisation, Denton adds a compelling catalogue of peculiarities of water such as surface tension, solubility, viscosity, heat capacity, and transparency, that together make water eerily well suited for life's activities. The game now is to see how far we can pursue this line of thought into the much more challenging area of molecular biology. But repeatedly the "too good to be true" principle emerges. Despite its iconic status the extraordinary nature of DNA is seldom appreciated, not least its ability to coil so effectively that the metre length encapsulated in each of your cells is comfortably accommodated in "a tiny ball about five microns (five-thousandths of a millimetre) in diameter". More specifically, are the four base pairs that form the backbone of the famous double helix simply good enough or uniquely suitable? Few alternatives appear to be available, and they may suffer severe defects. Denton freely admits that in this and many other cases the indications for unusual, if not unique, excellence are strong, but the evidence to date falls short of overwhelming.

Until we can either synthesise alternatives and place them in credible evolutionary contexts or stumble across a planet where there are plants but no chlorophyll, and eyes but no rhodopsin, then Denton's critics will always plead for a substitute. But the exactness of fits are extraordinary and when elsewhere other mainstream scientists refer to a protein (in this case haemoglobin) as "perfectly designed" or the genetic code for amino acids as "literally one in a million" one is anxious for the alternatives to be put on the table. Where I would take issue with Denton, however, is on the mechanisms of evolution. He is careful to distance himself from the creationists, but there is still a strong strand of anti-Darwinian thinking combined, unsurprisingly, with a sympathy for saltatory mechanisms. Much is made, for example, of the peculiar rectilinear eye of the lobster, and the difficulty of imagining either the transition from the usual compound eye of arthropods or how it achieves its change in function. But what is the problem? As Mike Land reminded me, the transition can be tracked through the ontogeny of the larval lobster, and the remarkable mirrored system of the adult eye is a clever adaptation to the dim zone of habitation.

If those espousing the forces of contingent evolution, the haphazard emergence from a chaos of alternative pathways, have rejoiced the loudest, it is with the origin of man. In a Shakespearian parody they declare: "How muddled in reason, how limited in his faculties, how crippled by ancestry, how like an animal, a Caliban, a creature of the ooze", and so exulted in our material bonds and limitations. How unlikely it is, they insist, that anything remotely similar to us could appear anywhere else. The realities of evolutionary convergences have already given us pause for thought, and now Denton extends his argument for the likelihood of hominid design by considering the essential nature of fire in the development of any technological species, first for protection and subsequently metallurgy.

This would seem to rule out any animal that remains aquatic. Then there is the curious fact of the controlled combustion of wood, but one that also presupposes a species with both an ability to manipulate objects and a size commensurate to the task. In their different ways, and no matter how intelligent dolphins and ants may be, they are not in this picture.

The magnitude of the task Denton has set himself is apparent from the need to supply an overarching teleology. In places his arguments look like special pleading, but it is perhaps more constructive to suggest, as Denton does little more than hint, that any teleological approach must have theological implications. The reasons for this should be clear. An argument for biological design presents obvious parallels to the problem of living in a pre-arranged universe that still permits our freedom of action.

If orthodox Christianity has an attraction to a scientist it is because it refuses to duck this intellectual problem. The theological solution is highly unfashionable but, to put it bluntly, if we have choice then this must allow the existence of hell. So too might we seek an analogy in the natural world. That life in its various manifestations is entirely dependent on H2O, four nucleotides, and chlorophyll has not trammelled the exuberance of the creation. And this is perhaps the most exciting prospect of Denton's book. Unlike these modern-day adherents to the fallacy attacked by Aquinas, that religion and science must occupy separate spheres of activity and influence, Nature's Destiny is a potential contribution to the makings of both a reconciliation and synthesis. It is no coincidence that Denton's language is one of awe and worship, and neither is it surprising that the medieval concepts of "being" versus "becoming" are taken seriously. So too should this book be.

Reg Morrison's The Spirit in the Gene is a dark and excitable book, brimming with angst and set against a lurid background of genetic determinism. Man's rationality, so we are to believe, is no more than a delusion. In reality we are genetic zombies, helplessly manipulated by a chemistry that demolishes free will and dismisses the religious sense as "truckloads of mystical nonsense". What an odd book. It begins with a litany of environmental destruction and degradation that makes for suitably grim reading. Things are not looking too good, but like any other plague species the laws of nature will inexorably push us back into the mire. Against this background, so Morrison argues, to believe we are capable and responsible agents is a delusion. Rather, because genetically we are hard-wired for an existence that was harmless in the jungle, it now reduces us to automatons that stroll to self-imposed destruction. Morrison does his best to assure us that it is not the actual genes, those innocent strings of nucleotides, that are the real culprits, but when one reads of "complex bargains (of human behaviour) hammered out in secret by opposing gene committees", one begins to wonder.

How seriously are we to take Morrison? That I cannot write this article without the ultimate operation of DNA is self-evident, but to argue that it provides the sanction is hopelessly simplistic. That I am greedy and inconsiderate is, no doubt, beyond dispute, and I may not be unique in this respect. But no sequence of nucleotides will emerge from the Human Genome Project, the deletion of which will remove these unworthy characteristics.

Morrison, however, fondly believes that somewhere in our genome is a factor X whose discovery will reveal at last our gullibility and lust. If it were only so simple. Morrison's diagnosis of looming environmental disaster is surely correct, yet his argument for genetic determinism is over-extended and gives no real remedy for a solution other than by self-induced catastrophe. In this book anger and facile assumptions lead to a disjointed jeremiad.

Of the last book, A Walk Through Time , one need only note it is a toe-curling embarrassment. Its essence is captured by a picture of misty clouds with the caption "A moment of silence, please". Ostensibly a survey of the evolution of life, its television-style script is a meander along the Gaia hypothesis. Hidden not very deep is an odious pantheistic mish-mash of muddled emotions and a suspicion of the human enterprise. This syrupy New Age wallow will, of course, be immensely popular.

Simon Conway Morris is professor of evolutionary palaeobiology, University of Cambridge.